Saw blade

ABSTRACT

The saw blade has a base body on which are mounted uncrossed teeth with cutting edges. The teeth are combined to form successive groups of at least three teeth and are disposed symmetrically to the longitudinal center plane of the base body. The teeth of one group increase in height from tooth to tooth while simultaneously decreasing in width.

BACKGROUND OF THE INVENTION

The invention relates to a saw blade, having a base body on which aremounted uncrossed teeth with a cutting edge. The teeth are combined toform successive groups of at least three teeth and are disposedsymmetrically to the longitudinal center plane of the base body.

When sawing through solid material, in particular metal, high frictionand impact stresses occur at the saw teeth. Owing to the high stresses,the saw teeth are fashioned from extremely hard material. In thecircular saw and band saw industry, it is standard practice to useuncrossed teeth in combination with different tooth-point forms for theprecutting and re-cutting geometry to reduce the stress on the sawteeth. This principle includes successive groups of teeth, comprising 2teeth each, of which the respectively first tooth, called thepre-cutter, is cut at a strong phase angle on the side and is somewhatlonger than the following, only minimally phase-cut second tooth, calledthe re-cutter. A saw blade of the aforementioned type is already known(compare the DE 43 00 622 C2). At least two groups of teeth, nestledinto each other, are mounted on the known saw blade. The first one ofthe two groups consists of at least two teeth, which decline in heightfrom tooth to tooth while simultaneously increasing in width. The secondgroup of teeth comprises at least two teeth, designed identically. Theseare the teeth with the largest width and the lowest height. The knownsaw blade has the disadvantage of being relatively sensitive to impactas a result of the first and at the same time highest tooth of the firstgroup of teeth, and additionally being subject to high wear and tear.

SUMMARY OF THE INVENTION

The invention is intended to remedy this problem. It is the object ofthe invention to create a saw blade having a low sensitivity to impactand being subject to low wear and tear while simultaneously generating astable movement in the cutting channel, as well as a good surfacequality.

This object is solved according to the invention in that the teeth of agroup increase in height from tooth to tooth while simultaneouslydecreasing in width.

The saw blade produced according to the invention is not susceptible toimpact and is durable. In addition, the vibrations normally occurringduring the sawing are reduced. The service life is increased while thecutting result is improved at the same time.

Embodiments and modifications of the invention are described in thedependent claims. One exemplary embodiment of the invention is shown inthe drawings and is explained in detail in the following.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view from the side of a saw blade with four uniformly spacedteeth.

FIG. 2 is a view from above of the saw blade illustrated in FIG. 1.

FIG. 3 shows the saw blade illustrated in FIG. 1, as seen from the left.

FIG. 4 is a view from the side of a section of a saw blade with twogroups of teeth and varied spacing.

FIG. 5 is a view of a group of teeth with varied phase angles,corresponding to FIG. 3.

FIG. 6a is a view from the side of a tooth with cutting separator.

FIG. 6b is a view from above of the tooth shown in FIG. 6a.

FIG. 7a is a view from the side of a tooth with roof.

FIG. 7b A view from above of the tooth shown in FIG. 7a;

FIG. 8a A view from the side of a tooth with cutting guide;

FIG. 8b A view from above of the tooth illustrated in FIG. 8a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The saw blade selected as exemplary embodiment has a base body 1. Theuncrossed teeth 2 are mounted on the base body 1. The teeth 2 aredisposed to form groups of at least three teeth.

Each tooth 2 has a tooth back 21 on its end facing away from the basebody 1. On the side facing the cutting direction X (FIGS. 1 and 2), eachtooth 2 has a tooth front 22. The tooth front 22 is arranged at aneffective cutting angle α to the vertical line. The effective cuttingangle can vary within a tooth group, but is remains in a region thatdrifts in a direction counter-clockwise to the vertical line. The toothback 21 for each tooth 2 is arranged at a clearance angle β to thehorizontal line for the saw blade. The clearance angle β is alwayslarger than 0°. The tooth back 21 and the tooth front 22 of each tooth 2are always arranged at a wedge angle γ to each other, which is in eachcase smaller than 90°.

The teeth 2 have a phase angle δ (FIG. 3). The phase angle δ can beselected to be in the range between 5° and 60°. Also, the phase angle δcan vary from tooth to tooth within a tooth group, as is shown in theexemplary embodiment according to FIG. 5 where the phase angle δ variesbetween 30° and 60°.

The height h of teeth 2 that are combined to form a group of teethincreases from tooth to tooth while the width b of teeth 2 that arecombined to form a group decreases at the same time. From this, itfollows that the lowest tooth of a group is simultaneously the widesttooth while the highest tooth is also the narrowest one. The increase inheight from tooth to tooth is at least {fraction (1/1000)} mm, but nomore than {fraction (5/100)} mm. The decrease in width is designed tolaterally separate a subsequently cutting tooth in the cutting channelfrom the pre-cutting tooth.

The teeth 2 are combined into groups of teeth comprising at least threeteeth. The groups of teeth succeed each other cyclically on the sawband. It is possible in this case that identical groups of teethrespectively follow each other. It is also possible that the successivegroups of teeth each have a different number of teeth (FIG. 4). In thatcase, a group G1, comprising four teeth, succeeds a group G2 with threeteeth. The group G2 is then followed again by a group G1. The groups ofteeth G1 and G2 are not nestled into each other. All groups of teeth ofthe saw band increase in height from tooth to tooth and decrease inwidth from tooth to tooth. The saw blade partition, that is to say thespacing of the teeth, can be selected to be constant or variable.

For the tooth shown in FIG. 6, a cutting divider 3 with narrow phaseangle is ground into the tooth back 21 of tooth 2. The cutting divider 3again divides the cutting or makes it smaller. The width and depth ofthe cutting divider 3 is 0.01 mm to 0.04 mm.

According to FIG. 7, the roof tooth 4 is arranged on the tooth front 22of tooth 2. The roof tooth 4 is formed by grinding the tooth front 22 atan angle ε. The angle ε preferably is in the range between 1 and 15°.The roof tooth 4 on tooth 2 further reduces the impact stress of thetooth on the material to be cut because only the tip of roof tooth 4impacts with the material to be cut, thereby causing the cutting to rollover the tooth tip.

A cutting guide stage 5 is provided for the tooth illustrated in FIG. 8.The cutting guide stage 5 is formed by a radius at the end of toothfront 22, which faces away from the base body 1 of the saw blade. Theradius preferably is in the range of between 0.1 and 1 mm. The cuttingguide stage 5 is used for materials such as austenites. These materialshave a tendency to heat up strongly during the cutting. The hot cuttingrolls off into the tooth gap, where it is welded on during the coolingdown and “adheres” to the spaces between the teeth when the tooth leavesthe cutting channel. Upon reentering the cutting channel, there is notenough space for the following cutting. The cutting space fills upcompletely with cuttings, causing the tooth to leave the cutting line.The cutting guide stage 5 guides the hot cutting into a smaller radiusand thus away from the surface of the cutting space. During thecooling-down phase, the cutting has no contact with the saw blade anddrops off without problems upon leaving the cutting channel. Thedescribed, varied geometries can all be mutually linked. The linking ofthese geometries causes each tooth within a group to perform a differentoperation within the cutting channel. Vibrations that normally occurduring the sawing are reduced or even eliminated as a result of thedifferent forces exerted on the individual teeth during the sawing, thedividing of one cutting into several fine cuttings, and the centering ofthe saw band owing to the superior tooth points, which are cut at astronger phase-angle.

What is claimed is:
 1. A saw blade comprising a base body having alongitudinal central plane, and a plurality of uncrossed teeth eachhaving a tooth front on which a cutting edge is disposed, and a toothback, said teeth being combined into successive groups of at least threeteeth and disposed symmetrically to the longitudinal center plane of thebase body, wherein the teeth of a group increase in height from tooth totooth in a direction from the tooth front to the tooth back whilesimultaneously decreasing in width from tooth to tooth in the directionfrom the tooth front to the tooth back.
 2. A saw blade according toclaim 1, wherein the teeth have a variable spacing between successiveteeth.
 3. A saw blade according to claim 1, wherein each grouprespectively comprises a variable number of teeth.
 4. A saw bladeaccording to claim 1, wherein the blade cuts in a cutting direction anddefines a vertical direction perpendicular to the cutting direction, andeach of the teeth has a cutting angle (α) from the vertical direction,provided in a range extending towards the cutting direction from thevertical direction.
 5. A saw blade according to claim 4, wherein thecutting angle (α) varies between respective teeth within a tooth group.6. A saw blade according to claim 1, wherein the teeth have a horizontaltop surface and a pair of angled surfaces which are angled relative tothe horizontal top surface by phase angles (δ) in the range between 5°and 60°.
 7. A saw blade according to claim 6, wherein the phase angles(δ) vary between respective teeth within at least one of the toothgroups.
 8. A saw blade according to claim 1, wherein the teeth eachcomprise a back side having a cutting divider.
 9. A saw blade accordingto claim 1, wherein the teeth each comprise a front side having a rooftooth.
 10. A saw blade according to claim 1, wherein the teeth eachcomprise a cutting guide stage.